(1) raw material, that is strip steel coil, welding wire, flux. Before investing, we must undergo a rigorous physical and chemical examination.

Spiral tube

Spiral tube

Spiral steel pipe in production

Spiral steel pipe in production

(2) single end or double wire submerged arc welding is adopted for the end to end of the strip. Submerged arc welding is used to weld the steel pipe.

(3) before forming, the strip is treated by leveling, trimming, planing, surface cleaning, conveying and bending.

(4) use the electric contact pressure gauge to control the pressure of both sides of the conveyor to press down the cylinder, so as to ensure the smooth transportation of the strip.

(5) adopt external control or internal control roll forming.

(6) the gap control device is adopted to ensure that the weld gap meets the welding requirements, and the pipe diameter, the error margin and the weld gap are strictly controlled.

(7) internal welding and external welding are made by American Lincoln Electric welding machine with single wire or double wire submerged arc welding, so as to obtain stable welding specification.

(8) the welded seams are checked by on-line continuous ultrasonic automatic instrument test, and the coverage rate of nondestructive testing of 100% spiral welds is guaranteed. If there is a defect, automatic alarm and spray mark, production workers at any time to adjust the process parameters, timely elimination of defects.

(9) the air plasma cutter is used to cut the steel tube into single parts.

(10) into a single tube, each batch of steel tube head three to strict inspection system first, chemical composition and mechanical properties of weld, inspection, blending, surface quality of steel pipe as well as a nondestructive inspection, to ensure that the process of good control, can be formally put into production.

(11) there is a continuous acoustic inspection mark on the weld seam. After manual ultrasonic examination and X ray examination, if there is any defect, after being repaired, it will be subjected to nondestructive testing again until the defects have been eliminated.

(12) strip butt weld and intersect with the spiral seam type joint in the tube, all through X ray TV or film examination.

(13) each steel pipe is subjected to hydrostatic pressure test, and the pressure is sealed in radial direction. The test pressure and time are strictly controlled by the steel pipe water pressure microcomputer detecting device. Automatic recording of test parameters.

(14) the end of the pipe is machined so that the verticality of the end face, the slope angle and the obtuse edge are accurately controlled.